Decolorizable ink and printer

Abstract

Decolorizable ink consisting of an ink composition dispersed in a solvent, the ink composition comprising a color former, a developer and a decolorizer, wherein the color former and developer are in a colored state by interaction between them and the decolorizer has a property to dissolve preferentially the developer when the ink composition is melted.

We claim: 
     
       1. Decolorizable ink consisting of an ink composition dispersed in a solvent, said ink composition comprising a color former, a developer and a decolorizer, wherein said color former and developer are in a colored state by interaction between them and said decolorizer has a property to dissolve preferentially one of said color former and developer when the ink composition is melted, and   wherein said decolorizer is selected from the group consisting of cholic acid. lithocholic acid, testosterone, cortisone and their derivatives.   
     
     
       2. The decolorizable ink according to claim 1, wherein said developer is contained in an amount of 0.1 to 10 parts by weight relative to one part by weight of said color former. 
     
     
       3. The decolorizable ink according to claim 1, wherein said decolorizer is contained in an amount of 1 to 200 parts by weight relative to one part by weight of said color former. 
     
     
       4. The decolorizable ink according to claim 1, wherein said solvent is water. 
     
     
       5. The decolorizable ink according to claim 1, wherein the ink composition is dispersed in the solvent in the form of microcapsules. 
     
     
       6. The decolorizable ink according to claim 1, wherein a concentration of the ink composition in the solvent is in the range of 0.1 to 10 wt %.